Yarn carriers for package dyeing have been traditionally formed as perforated tubes or axially compressible springs. A package of yarn is wound onto the carrier and the carrier-supported yarn package is mounted coaxially on a post in a package dyeing machine. Additional yarn packages are then stacked on the post, one above the other with or without spacers between adjacent packages, until the post is filled. Pressure is typically applied to the yarn packages on each post and the package dyeing machine is then sealed and dye liquor is pumped into, and out of, the posts supporting the yarn packages. As a result, dye liquor is pumped through the yarn packages supported on the posts and the yarn in the yarn packages is uniformly dyed.
When the yarn packages are supported on spring carriers, the spring carriers are axially compressed just prior to the dyeing operation. This is accomplished by applying a substantial axial pressure to a full stack of dye spring-supported yarn packages positioned on a dyeing post. Sufficient pressure is applied to partially collapse each of the dye springs which causes the individual yarn packages to contact each other at their adjacent axial ends. The resultant stack of yarn packages then takes a visible form similar to a single elongated yarn package. This well known dyeing process provides more even dyeing of yarns in many instances.
For many years, both rigid carriers (which are not collapsed during dyeing) and spring carriers for package dyeing of yarn were formed of metal, typically stainless steel. with the advent of structurally stable plastic materials over the past decades, construction of carriers for yarn package dyeing has increasingly been based on the use of plastic materials such as polyolefins, nylon, polyesters and the like. Rigid carriers for package dyeing of yarns have been constructed as perforated plastic tubes, generally the same as with prior perforated metal tubes, but typically including structural modifications for strengthening of the perforated plastic tubes because of the weaker structure of plastics as compared to metals. In the case of dye springs, plastic carriers are formed in various structures including structures using a plurality of straight or curved bendable ribs or rib-like structures distributed longitudinally along the length of the yarn carrier and evenly around the circumference of the carrier. Axial pressure applied to the plastic spring carrier results in bending or folding of the ribs resulting in the compression and axial shortening of the spring carrier.
In prior practice, dyed yarn packages were normally transferred to a different yarn carrier prior to downstream operations for forming the dyed yarn into end products such as cloth. Because of various improvements in package winding and dyeing processes, rewinding operations between package dyeing and end product formation have been eliminated in many cases so that in these instances the same yarn package carrier is used in dyeing and in the end product forming process. Such yarn packages have become known as "direct ship" packages.
Textile intermediate and end products such as beams, cloth, thread and the like, are generally formed from a plurality of yarn packages which are tied together to provide a generally continuous single yarn having a total length the same as the plurality of packages. This has long been accomplished by forming a yarn transfer tail on a portion of the yarn package carrier during the beginning of the yarn winding operation. The transfer yarn tail generally comprises a plurality of turns or windings of the yarn, sometimes called a "bunch", which are segregated from the main yarn package at a special location on the yarn carrier, normally at one end of the carrier. In a knitting, weaving or other yarn conversion process, the transfer tail from a first package (constituting the tail end of that package) is tied to the starting end of the following yarn package so that during the conversion operation, when the yarn on the first package is exhausted, the conversion operation is transferred to the next package by the transfer tail of the first package so that the conversion operation continues without interruption.
Because the yarn transfer tail must be generally accessible during the subsequent yarn conversion operation, the transfer tails are normally found at or adjacent one end of a yarn carrier. Typically, the transfer tail bunch is segregated from the main yarn package by means of a groove. The groove entraps the transfer tail bunch because the groove has a smaller circumference than the outside surface of the rest of the carrier and also because of the sidewalls of the groove. However, in the case of dye springs, collapse of the yarn carrier during the package dyeing operation causes the disappearance of the exposed ends of the yarn carrier because these ends are compressed toward each other and ultimately become disposed beneath the ends of the yarn package.
Accordingly, transfer tail bunches on dye springs, if formed on the ends thereof, can be difficult to separate from the main package following dyeing. In order to avoid this problem, in many cases the transfer tail is not formed on the surface of the yarn carrier during winding. Instead, the transfer tail is formed on a nesting collar which extends axially from one end of the yarn carrier. The nesting collar has a smaller outside diameter than the outside diameter of the main body portion of the carrier. Traditionally, such collars have been used to ensure a proper engagement and axial alignment of axially stacked yarn packages during dyeing and transport of the packages. This is achieved by inserting the axially extending, smaller diameter, nesting collar on one end of a first yarn package into the interior of a larger female collar on the opposite end of an adjacent yarn carrier so that the two yarn carriers are aligned and stably joined to each other. A plurality of such carriers can be axially stacked to provide for stable stacking during dyeing and easy transport of empty carriers or carriers bearing yarn packages following a winding or dyeing operation. Stable stacking of yarn packages can also provide a substantial space savings during transportation of the packages because a single pallet can be used to support a plurality of stacked layers of yarn packages.
Yarn carriers having various modifications to facilitate nesting during dyeing and/or transportation are disclosed for example in U.S. Pat. No. 2,489,465 to Russell; U.S. Pat. No. 4,946,114 to Becker et al.; U.S. Pat. No. 4,331,305 to Marquis et al.; and U.S. Pat. No. 4,270,710 to Ono. Dye spring carriers having an axially extending smaller diameter nesting collar including a transfer tail groove on the nesting collar are disclosed in U.S. Pat. No. 4,702,433 to Gilljam et al.; U.S. Pat. No. 4,941,621 to Pasini; and U.S. Pat. No. 4,997,141 to Pasini. In these yarn carriers, the axially extending collar having the yarn tail groove formed thereon extends into the interior of an adjacent yarn carrier during a dyeing operation.
Although entrapment of the transfer tail bunch within a groove on a nesting collar of a dye spring can maintain the transfer tail bunch separate during a dyeing operation, various other difficulties are created by this arrangement. Specifically, in order that the transfer tail bunch be stably retained in a transfer tail groove, several windings of yarn must be orovided in the groove in order to generate sufficient friction between the overlapped windings that the tail doesn't simply slip out of the groove during transport of the yarn package. However, it can then be difficult to uniformly dye the overlapped transfer tail windings because the transfer tail bunch is located in a narrow annular space between the nesting collar and the inside surface of an adjacent dye spring during the dyeing operation. The flow of dye through this annular area is generally not the same as the flow of dye through the yarn packages. Moreover, the transfer tail windings are generally oriented in a tight coaxial and overlapping relationship with respect to each other so that contact between the dye liquor and the yarn surfaces can be insufficient to achieve good dyeing, particularly in the lower windings in the groove. Still further, pinching of yarns between the nesting collar and the inside or end surface of the adjacent yarn carrier must also be avoided because pinched yarn surfaces are generally not evenly dyed during a dyeing operation. Moreover, in the case of many delicate yarns, such as low count spun yarns, pinching of the yarn can sever the yarn, thus destroying the transfer tail.
In order to avoid pinching the segment of yarn joining the transfer tail bunch to the main yarn package, various modifications are normally included in dye spring yarn carriers having a transfer tail groove formed on She surface of a nesting collar. Normally, these modifications include the provision of a radial space between the outer surface of the nesting collar and the inside surface of the female collar of the adjacent carrier so that the yarn segment which exits the transfer tail groove is not pinched in the radial direction between the nesting collar and the inside surface of the female collar of the adjacent tube. In addition, an axial space is normally provided between the shoulder joining the nesting collar to the main body of the yarn package, and the bottom end face of the adjacent yarn package. This is normally achieved by the inclusion of axial stops, i.e., axial engagement surfaces, between the two yarn packages. However, the provision of such axial and radial spacing between engaged male and female collars decreases the positive engagement between the nesting collars so that stable axial stacking of adjacent yarn packages is correspondingly more difficult. In addition, yarn carrier modifications to improve the positive engagement between the two larger and smaller nesting collars generally result in the provision of obstructions that can interfere with the flow of dye liquor to the transfer tail windings entrapped by a groove on the male nesting collar, and can also be costly because of the plastic materials needed to provide such positive engagement surfaces and also because of mold modifications that must be carefully and precisely made in order to provide such modifications.